Is the United States on the verge of running out of Social Security Numbers? After
revealing that the Social Security Administration actually has a system for assigning
SSNs, Doctor Wallace clears up the combinatoric calculations, then predicts how much longer the available pool will last.

I have heard that Graham's number is the largest number with
mathematical use. I have seen it expressed in arrow notation but
that does not give me a sense of how large it is. Is there a way to
express the number of digits it contains?

When I was in 8th grade my math teacher said duodecillion was the
largest number of anything in the world that is measurable. Can you
tell me what that 'thing' is that measures a duodecillion? What's the
biggest number we know of or use?